Bad RequestBypassToServer:
java.lang.NullPointerException
        at net.sf.l2j.gameserver.handler.SkillLearnModTable.isStacking(SkillLear
nModTable.java:115)
        at net.sf.l2j.gameserver.model.actor.instance.L2PcInstance.giveAvailable
Skills(L2PcInstance.java:2243)
        at net.sf.l2j.gameserver.model.actor.instance.L2PcInstance.rewardSkills(
L2PcInstance.java:2186)
        at net.sf.l2j.gameserver.model.actor.instance.L2ClassMasterInstance.onBy
passFeedback(L2ClassMasterInstance.java:279)
        at net.sf.l2j.gameserver.clientpackets.RequestBypassToServer.runImpl(Req
uestBypassToServer.java:107)
        at net.sf.l2j.gameserver.clientpackets.L2GameClientPacket.run(L2GameClie
ntPacket.java:76)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source
)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
        at java.lang.Thread.run(Unknown Source)



===================================================================================
@L2PCInstance.java

	/**
	 * Give all available skills to the player.<br><br>
	 *
	 */
	private void giveAvailableSkills()
	{
		int unLearnable = 0;
		int skillCounter = 0;

		// Get available skills
		L2SkillLearn[] skills = SkillTreeTable.getInstance().getAvailableSkills(this, getClassId());
		while (skills.length > unLearnable)
		{
			for (int i = 0; i < skills.length; i++)
			{
				L2SkillLearn s = skills[i];
				L2Skill sk = SkillTable.getInstance().getInfo(s.getId(), s.getLevel());
				if (sk == null || !sk.getCanLearn(getClassId()) || (sk.getId() == L2Skill.SKILL_DIVINE_INSPIRATION && !Config.AUTO_LEARN_DIVINE_INSPIRATION) || !SkillLearnModTable.getInstance().isStacking(_activeRequester, i))
				{
					unLearnable++;
					continue;
				}

				if (getSkillLevel(sk.getId()) == -1)
					skillCounter++;

				addSkill(sk, true);
			}

			// Get new available skills
			skills = SkillTreeTable.getInstance().getAvailableSkills(this, getClassId());
		}

		sendMessage("You have learned " + skillCounter + " new skills.");
	}

That's what I changed :P Line 42